EddieWalker
Epic Contributor
The minimum concerte cover for rebar is 3". That is to protect it from salt, water, etc. Also, the only time rebar does any good for structural strength is when it is placed in the bottom of the concrete slab as steel has great tensile strength where concrete has viturally none. Rebar only begins to take a load wonce the concrete actually cracks. In school we tested concrete beams 6"x6"x24" for flexural strength. Without fiber mesh they would break within a few cycles...with it they could continually take flexural forces indefinately. If you have a good base you will probably not have flexural forces. The number one problem with concrete failing is excessive water added on site...hands down. Concrete strength is solely dependent on the water to cement ratio.
I agree with some of what you say, but disagree with some of it too. Are you in the trades? what school took a concrete beam and found it stronger with fiber? I don't want to disagree with you, but I find this just about impossible to believe? Same with rebar requireing 3 inches of concrete over it. That would be a failure of placement in a 3 1/2 inch pad and result in excessive cracking.
I agree that too much water will destroy the PSI of concrete, but other factors also have a huge impact on how strong it is. How much Cement is added to it, the size of the agrigate, the temperature when it poured and how long it has to cure.
Eddie